Microsoft’s chief product officer Panos Panay once said “If you’re a gamer, Windows 11 was made for you.” Unfortunately, a couple of days after launching, it’s turning out to be something of an unwanted gift. Besides being blamed for Far Cry 6 crashes and deterring an entire cloud gaming service, Windows 11 is now causing performance drops on AMD chips as well. That’s according to AMD themselves, who announced in a support post that updating to Windows 11 could cause a 3-5% performance drop in some applications as well as a 10-15% drop in “games commonly used for esports.”
This is apparently affecting, or has the potential to affect, all AMD chips that officially support Windows – that’s dozens and dozens of processors, including the AMD Ryzen 5 5600X that sits atop our best CPU for gaming list. Both AMD and Microsoft are “actively investigating” fixes, with a view to launching separate software and Windows updates within this month (October 2021).
According to AMD's post, there are two distinct issues when pairing Windows 11 with an AMD CPU. The first, and most worrying for games performance, is a huge increase in L3 cache latency: in the Queen’s English, that means one of an affected CPU’s memory banks slows down, making it take longer to access data stored in the main system memory. “Games commonly used for esports” is perhaps intentionally vague but likely refers to less graphically demanding but memory- and CPU-sensitive games like Counter-Strike: Global Offensive and Dota 2. A 10-15% drop could be easily noticeable, especially if you’re playing at 60fps or lower, though AMD’s post calls such examples “outliers” so the 3-5% reduction is probably much more common. Even so, s’a bit rubbish.
The second problem is AMD’s “preferred core” tech not accurately allocating applications to the fastest cores on an affected CPU. There’s no scary sounding percentages given here, but as a lot of games still only use one or two cores at a time, it’s not hard to imagine this might hurt frame rates as well. “Performance impact may be more detectable in >8-core processors above 65W TDP,” so says the post, though that doesn't mean 6-core chips (like the Ryzen 5 5600X) and below are immune.
It’s good that AMD and Microsoft are both so well aware of these problems that they have an ETA for fixes, albeit a broad one. But man, Windows 11 is really struggling to stick the landing. Launching without game support for its flagship DirectStorage feature is one thing , but actively tripping up Ryzens? For something that’s supposedly made for gaming, Windows 11 is providing an awful lot of reasons to pass on it.